Problem: Solve for $x$ : $5\sqrt{x} + 6 = 2\sqrt{x} + 4$
Subtract $2\sqrt{x}$ from both sides: $(5\sqrt{x} + 6) - 2\sqrt{x} = (2\sqrt{x} + 4) - 2\sqrt{x}$ $3\sqrt{x} + 6 = 4$ Subtract $6$ from both sides: $(3\sqrt{x} + 6) - 6 = 4 - 6$ $3\sqrt{x} = -2$ Divide both sides by $3$ $\frac{3\sqrt{x}}{3} = \frac{-2}{3}$ Simplify. $\sqrt{x} = -\dfrac{2}{3}$ The principal root of a number cannot be negative. So, there is no solution.